Everything comes back to Jesus.  It is all about Him.  Fortunately, we have the most evidence for Jesus, His death, and His resurrection.  

I have a simple logical argument that can be simplified in this equation:

Notably, this argument comes primarily from the mind and scholarship of Dr. Gary Habermas.[3]  His bookThe Historical Jesus, among many others is absolutely invaluable to apologetic efforts.  I highly recommend his work.  Lee Strobel is also a good author on the subject.  His book The Case for Christ has helped many come to faith.  I think you will find Strobel easier to start with.  Habermas is a good next step.

There are 4 primary criteria that must be met for a first century historical document to be considered reliable:

• Number of copies (the more the better, at least 26)
• Few Variant Readings (the fewer contradictions between copies, the better)
• Date of Writing (the earlier, the better)
• Number of Sources (the more corroborating, the better)